The invention relates to a roller chain for chain drives, having a plurality of inner links and outer links, the inner links having at least two inner plates provided with two pairs of coaxially aligned pin holes and with pin bearings disposed between the holes, the outer links containing at least two outer plates each which are joined together by at least two pins fastened to them, the one pin of each outer link passing through one of the pairs of pin holes and the associated pin bearing of one of the adjacent inner links, and the other pin of each outer link passing through one of the pairs of pin holes and the associated pin bearing of the other of the adjacent inside links, for the purpose of the pivotal joining of the outer links to each two adjacent inner links, and the pin bearings being surrounded by rollers disposed in a loosely rotatable manner between the inner links. Such roller chains are suitable especially for the chain drives of motorcycles or bicycles with or without derailleurs.
Roller chain drives are among the power transmission systems of high efficiency, light weight and sturdy construction which are able to transmit great forces over great distance between shafts. The chain is the power transmission means. In sprocket-changing drives (hereinafter called "derailleurs") the chain is at the same time the shifting means. Generally, roller chains are used which have different kinds of plates. The links are so constructed that the pins of the outer links rotate in sleeves of the inner links, the sleeves being fastened nonrotatably on the inner plates and additional rollers being mounted rotatably on the sleeves.
In the roller chains used heretofore, the following problems are known:
The link wear which develops due to the pivotal movement of the chain links under load as they engage and disengage the sprocket causes an increase in the effective pitch. The length of the chain increases accordingly. This elongation due to wear is nonuniform in conventional sleeve and roller chains. Due to the resulting nonuniform meshing of the chain, a uniform engagement of chain and sprockets is no longer possible. The result is increased wear on the flanks of the sprocket teeth.
In conventional roller chains, the magnitude of the effective bearing surface necessary for the transmission of the chain forces is dependent upon the bearing clearance between pin and sleeve. This bearing clearance must be relatively great. This results in unfavorable link stress conditions.
In conventional chains, in order to assure easy running, not only the links but also the rollers must be well lubricated. In the case of free-running chain drives, e.g., on bicycles, this results in the accumulation of dirt on the sprockets and on the chain itself, and calls for increased maintenance on account of the additional wear caused by the dirt adhering to the lubricant.
Furthermore, conventional roller chains entail numerous problems if they are to be used in derailleurs.
It is therefore the object of the invention to create a roller chain in which the above-described problems and disadvantages will be eliminated. A further object of the invention is to replace the sleeves which are provided in conventional roller chains, and are affixed to the inner plates, with other components mainly for the purpose of reducing wear on the chains. At the same time these components are to be so designed that they will be easy and inexpensive to manufacture and assemble and will not impair the common function of a roller chain. Lastly the individual chain links are to be able to be deflected relative to one another by the greatest possible angle, as in conventional chains, this being desirable for packing purposes, and also for chain drives using extremely small sprockets.